U.S. Pat. No. 3,380,646 discloses a container of thermally weldable, plastic material and a method of producing the container by welding together multiple strips or sheets of plastic material to form a container having a welded closed, bottom part of the container. An open top of the container is collapsed and flattened to provide a pinch closed top.
U.S. Pat. No. 5,048,692 discloses a bag folded one or more times to form a primary closure. A flap seal extends across the folded configuration. A string underneath the flap seal is used to tear open the flap seal and permit the bag to unfold. A zipper closure provides a secondary enclosure.
US 2007/0292053 A1 discloses a bag of paper material and a paper tape coated with a hot melt adhesive, wherein the tape is folded to adhere the hot melt adhesive against a front panel of the paper bag to provide a glued paper-to-paper section. The tape substitutes for a stepped end of a multi-wall paper bag. The stepped end provides a sealing flap coated with hot melt adhesive, wherein the sealing flap can be folded over and sealed to the front panel of the paper bag.